Clinical Research Trials

Designing The Therapeutic Trials

Welcome to Clinical Research Trials - The Need of Statistics: After getting the overview of therapeutic trial, there arises the need for correct statistical information. When clinical impressions or convinced opinions are used instead of convincing facts, the progress is delayed and the condition becomes pitiable.

Statistics can be defined as 'a body of methods for making wise decisions in the face of uncertainty'. When used properly, it is a good tool for promoting efficient therapy.

Designing The Therapeutic Trial:

The general aspects of randomized controlled trials are given below. However, all of them can't be attempted on any one occasion.

• Ascertaining whether a treatment is of value.

• Compared with other treatments, how great its value is.

• In what types of patients it is of value.

• The best method of applying the treatment, the dosage and the frequency of the dosage.

• The disadvantage and the dangers of the treatment.

Brandoff Hill in his book 'Principles of Medical Statistics' defines the therapeutic clinical research trials as - a carefully ad ethically, designed experiment with the aim of answering some precisely framed questions. In its most rigorous form, it demands equivalent groups of patients concurrently treated in different ways. These groups are constructed by the random allocation of patients to one or other treatment.

Equivalent Group Of Patients In Clinical Research Trials:

When the treatment groups differ significantly in age, sex, race, duration of disease, severity of disease or another relevant factor, it won't be possible to attribute differences in outcome to the treatment under investigation. The best way of getting equivalent groups is by allocating patients to them by random allocation.

The function of the randomization is to eliminate systematic biases, both known and unknown that could affect assignment to treatment.

Time And Space Of The Treatment In Clinical Research Trials:

Treatments should be carried out at the same place and at the same time. The historical controls i.e. controls from the past are nearly unacceptable.

Precisely Framed Questions:

Formulating the exact questions that are to be answered is essential before the begining of the trial.

Ethics Of Clinical Research Trials In Man:

The research involving human subjects can be of two types - Therapeutic that which actually have a therapeutic effect and can help the participant.; Non-therapeutic that which provides information that can't be of direct use to participant like healthy volunteers and sometimes patients.

Our Right To Choose To Participate In Clinical Research Trials:

Potential participants have the right to autonomy i.e. they can choose for themselves whether or not to participate in the research. The issue of consent is prominent in discussions of the ethics of human experimentation and it is a principal concern of the Research Ethics Committees that are now the norm in medical  research.

European Journal of Clinical Pharmacology (1980; 18: 129) summarizes it in a report: "As physician investigators seed knowledge about the safety and efficacy of medicines, which is a social good, the dignity of individuals must not be overridden. The therapeutic trial is both ethically required for the social good of more effective medical care and is capable of being designed in ways that respect the wellbeing and rights of individual participants."

The overall objective of Clinical research trials must be that no patients should be worse off than he might have been in the hands of a reasonable and competent physician.

Interpretative Factors Of Clinical Research:

Some concepts need to be defined for interpreting the information received by therapeutic trial.

Hypothesis Of No Control:

 It is used to tell whether a treatment is equally effective or better or less effective than the other treatment in comparison.

Statistical Significance:

A statistical significance test will reveal how often a difference of observed size would occur due to chance or random influences, if there is no difference between the efficacy of treatments.

Confidence Intervals:

These reveal the precision of an estimate. A wide ranging confidence interval point to lack of information, whether the difference is statistically significant or not. It is a warning for placing much weight over such studies. Confidence Intervals are expressed as a range of values within which we may be 90% (or other chosen %) sure that the true value lies. Confidence intervals are extremely important in interpretation, particularly of small studies as they show the degree of uncertainty related to a result.

Types Of Error:

 It is up to the clinician to decide the target difference and the acceptable probability level for both types of error.

• Type One - Finding a difference between treatments when in reality they don't differ.

• Type Two - Finding no differences between treatments when in reality they  differ.

The Size Of A Therapeutic Clinical Research:

The number of patients required for a therapeutic trial depends on the difference that the investigator regards as clinically significant and the number of the patients available. The estimate is provided to the clinician by the statistician after the clinician tell him about the magnitude of interest and the acceptance of the errors. The size is adjusted in two different ways.

1. Fixed Sample Trials: It is decided beforehand - the difference to be sought;  the precision with regard to time, energy and numbers of patients available; the number of patients to be treated and the testing of the results. In this fixed sample trials, there is less likelihood of arriving at falsely significant difference. But at the end there may be disappointment when the desired results are not met.

2. Variable Number Trials: In this design the number of patients is not decided in advance. This clinical research trial is developed in response to the need of continuous or intermittent assessment as the trial proceeds. This trial stops either as soon as the statistically significant result is reached or when such a result becomes unlikely.

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The Preclinical or Animal studies - discovery to development of medicine - Its role in Herbal Research.

The Therapeutic trials  in Man - Its role in Clinical research trials of Herbal  Research.

How the Therapeutic studies are designed and What are the ethics of research in man? How are they sized appropriately?

What is double blind clinical research trials? Why are they necessary?

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